90 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
tion for the flies, evaporates slowly when diluted with water and with 
most of the chemicals employed no change took place between the medi¬ 
um and the odoriferous chemical. The chief objection to corn syrup 
was the fact that a resistant skin-like film forms over the liquid product 
upon exposure to hot sun and dry weather for several days. Brown 
sugar diluted with water, molasses and honey were useful media in 
many cases. In fact larger catches of flies often were made with these 
media than with corn syrup because they are attractive to flies by them¬ 
selves. This was particularly true of honey. One teaspoonful of the 
medium was placed in a Syracuse watch glass and about three tea¬ 
spoonfuls of water added. This nearly filled the dish. To the diluted 
medium the odorous agent was added. In case the agent was a liquid 5 
drops (amount most frequently used) were added and thoroughly 
mixed with the medium. If the agent was yeast a piece the size of a 
small pea was most frequently added. Where pieces of onion were used 
to 1 bulb (sliced) of a small green onion or a half dozen 1 inch lengths 
of a green leaf were added. 
The following odorous products and poisons were given one or more 
trials by themselves (in media) and in some cases in combination with 
each other: Oil of hemlock, sassafrass, pineneedles, spruce, nutmeg, 
cinnamon, mustard (true and artificial), phenyl mustard oil, orange, 
lemon, cloves, menhaden, camphor, anise seed, oleoresin capsicum 
(pepper), peppermint, spearmint, rose geranium, fusel and peach 
kernels; also formic acid, acetic acid, butyric acid, lactic acid, valeric acid, 
ammonia, formaldehyde, aldehyde, (ethylic acetic) creososte, linaly- 
acetate, acetone, amylacetate, allyl sulfide, allyl bromide, allyl iodide, 
allyl alcohol, milk (sweet, sour and powdered), dry compressed yeast 
(“Magic Yeast” and “Yeast Foam”) and wet yeast (“Fleischman’s 
Yeast”), onion (bulbs and tops), sodium arsenite, mercuric chloride, 
sodium fluoride, sodium cyanide, nicotine sulfate, hellebore, and ex¬ 
tracts of derris. 
Discussion 
Many and interesting observations will be omitted from this report. 
Only those points will be discussed which bear directly on the problem 
under discussion. 
The adult flies of Hylemyia antiqua Meig., and Hylemyia cilicrura 
Rond., are most active on warm dry days in the early hours of the morn¬ 
ing and toward evening, at least the great majority of the adults came to 
the cages during these hours. Cages placed in irrigated fields (over¬ 
head irrigation) usually did not catch as many flies as cages in open dry 
